The
gotcha that I still see is around interceptor bindings. They need to be explicitly disallowed on final methods, and big ole warning put in when you have interceptors on classes with final methods.
In my experience legacy (framework) code tends to have protected final methods, so the problems might be less dangerous than they appear first place (regarding interceptors).
I would just warn that a non-proxyable class is proxied, and certain problems arise by doing so. You can name the problems, sure. But I think it is ok to say (in bold): Yes, we do what you want. But live with the consequences.